Norway: Sulphur hexafluoride (SF₆), widely used to keep high-voltage switchgear safe, is coming under increasing pressure due to its extreme impact on the climate, estimated to be 24,300 times stronger than CO₂. As the European Union moves to phase it out, researchers are working to ensure alternatives can match its performance.
Switchgear play a critical role in protecting the grid. When faults occur, they must interrupt currents within milliseconds to prevent wider failures. The gas inside them not only insulates but also helps extinguish electrical arcs when contacts open. SF₆ has long been the preferred option because it performs both tasks exceptionally well.
However, replacing it is not straightforward. Alternative gases may react differently under high stress, varying temperatures, or after years of operation. Scientists must understand how these gases behave not only when new, but also after decades of use in sealed equipment.
This is the challenge that the Norwegian research project NEMEGIS, is designed to tackle. Short for “Next generation of environmentally-friendly gas-insulated switchgear”, the initiative aims to determine whether alternative insulation gases can match the long-term reliability of SF₆, not only when first deployed but over a full service life of 30 to 40 years.
To do this, researchers will combine experimental work with theoretical analysis, studying how the gases perform under electrical stress, varying temperatures and ageing. A key objective is to understand how their properties evolve over time inside sealed equipment.
Building on the earlier “New gases for GIS” project, which focused on the fundamental science of insulation and discharge behaviour, NEMEGIS moves closer to real-world application. It will bring together laboratory testing and operational data from SF₆-free switchgear already in service in Norway and across Europe, including accelerated ageing studies.
Led by SINTEF, the project started in Trondheim and will run until 2029, involving 25 partners from across the power sector value chain.
Source: SINTEF
